There are three principal objectives of the proposed intracellular studies of cochlear nucleus. The first aim is to develop a new method applicable to all in vivo intracellular studies for eliminating the problem of brain pulsations caused by the cyclical arterial and venous pressure fluctuations from cardiac and respiratory cycles. These physiological pulsations make penetration and staying intracellularly very difficult. A method for solving this problem will be developed using a centrifugal flow cardiopulmonary bypass-pump to generate a non-pulsatile perfusion of the cat's brain. The second major objective of this intracellular study is to correlate the structure and function of individual cochlear nucleus cells. This will be accomplished by first recording a response profile of each cell to a variety of acoustical stimuli (tone bursts, clicks and FM) and then subsequently injecting horseradish peroxidase intracellularly for morphological identification. The third objective is to study the synaptic mechanisms responsible for the complex response patterns recorded from cochlear nucleus cells. Specifically the following synaptic influences on cochlear nucleus cells will be examined: a) afferent input from eighth nerve fibers; b) input to dorsal cochlear nucleus cells originating in the ventral cochlear nucleus; and c) efferent inputs via the olivocochlear bundle.